1. Field of the Invention
The present invention relates to an immediate release guaifensin solution for oral administration and in particular, a guaifenesin solution which in addition to water, contains concentrations of propylene glycol and glycerol which significantly improve the bioavailability of the guaifenesin in the human body.
2. Discussion of Background Information
Orally administered pharmaceutical compositions are provided to patients in many dosage forms, including solid forms such as capsules, caplets or tablets and liquid forms such as solutions and suspensions. Due to these issues with swallowing, oral solutions are preferred for many pharmaceutical products, especially those products that will be used in children and geriatric patients. One such category is cough and cold products. As with all other dosage forms, it is desirable for oral dosage forms to provide a degree of bioavailability of the drug(s) to be administered that is as high as possible. It has now unexpectedly been found that by including two organic solvents, i.e., propylene glycol and glycerol, in an aqueous guaifenesin solution for oral administration the bioavailability of the guaifenesin can be improved significantly, as evidenced by, for example, a significantly increased Cmax (maximum plasma concentration) and AUC(0-inf) (area under the plasma concentration curve from zero to infinity).